Aromatic amine-modified resole resins in combination with aromatic polycarboxylic compounds

ABSTRACT

Thermosettable compositions of an amine-modified resole resin and an aromatic polycarboxylic compound. These compositions can be thermoset by heat with temperatures and times approaching those used for thermosetting ordinary resole resins along and the product thermoset articles display improved thermal stability.

United States Patent Huck AROMATIC AMINE-MODIFIED RESOLE RESINS INCOMBINATION WITH AROMATIC POLYCARBOXYLIC COMPOUNDS Rodney M. Huck,Longmeadow, Monsanto Company, St. Louis, Mo.

March 12, 1971 Inventor:

Assignee:

Filed:

Appl. No.:

[4 1 July 18,1972

[56] References Cited UNITED STATES PATENTS 3,558,559 l/1971 LeBlanc..260/51.5

Primary Examiner-Howard E. Schain Attorney-John W. Klooster, James C.Logomasini, Richard W. Stemberg and Neal E. Willis 57] ABSTRACTThermosettable compositions of an amine-modified resole resin and anaromatic polycarboxylic compound. These compositions can be thermoset byheat with temperatures and times approaching those used forthermosetting ordinary resole resins along and the product thermosetarticles display improved thermal stability.

11 Claim, No Drawings AROMATIC AMINE-MODIFIED RESOLE RESINS INCOMBINATION WITH AROMATIC POLYCARBOXYLIC COMPOUNDS BACKGROUND The arthas recently come to appreciate that thermosettable compositions of anaromatic amine-modified novolac resin and an aromatic polycarboxyliccompound, when thermoset, display improved thermal stability; see theLeBlanc US. Patent 3,558,559. Aromatic amine-modified novolac resinscharacteristically by themselves tHermoset poorly and characteristicallythey require another agent to induce good thermosetting by heat alone.

Amine-modified resole resins, on the other hand, characteristically, dothermoset well by themselves without the need for a curing agent.However, such modified resole resins when thermoset display at best onlythe typical heat stability characteristics commonly associated withphenolic resins generally; that is, they display maximum continuousservice temperatures on the order of about 250-400 F. or less whenmolded (with or without post-curing).

In general, it appears that, as the amine content of a resole resin isincreased, the ability of the resulting resin to thermoset by itself isdecreased. On the other hand, as the amine content of a resoleincreases, the capacity of the product resin to react (crosslink) with apolycarboxylic compound increases (assuming the amine reactivity, thatis, the quantity of primary and secondary amine groups present,correspondingly exists). Thus, in any given composition ofamine-modified resole resin and aromatic polycarboxylic compound, onemust compromise heat resistance of thermoset molded body withcomposition moldability.

Those skilled in the art will readily understand that such variables asthe nitrogen content of a starting resin, the reactivity of theindividual nitrogen groups, the extent of any residual phenolicreactivity, and the like all can efiect the maximum continuous servicetemperatures of a thermoset product. In turn, such variables can beaffected by such resin synthesis factors as catalyst, starting material,etc. and by such cross-linking reaction variables as rearrangements athigh temperature, etc.

It has now been discovered that, when an amine-modified resole resin iscomposited with an aromatic polycarboxylic compound, and then theresulting composition is thermoset, the resulting thermoset body has asurprisingly higher maximum continuous service temperature compared tothe aminemodified resole resin body cured by itself.

Furthermore, and unexpectedly, it has also now been discovered thatcompositions of amine-modified resole resin and aromatic polycarboxyliccompound can be molded at temperatures much below those necessary tomold compositions of aromatic amine-modified novolac resin and aromaticpolycarboxylic compound. Thus, while temperatures of from about 450 to650 F. are needed to mold aromatic aminemodified novolac resin/aromaticpolycarboxylic compound compositions, temperatures of only about 350 to400 F. are needed to mold compositions of amine-modified resole resinand aromatic polycarboxylic compound, these latter temperatures beingonly a little higher than those conventionally now used to moldone-stage resole resins. This difference in reactivity apparentlyresults from the circumstance that the phenolic portion of the resoleresin is still capable of self-thermosetting even though the reactivityof functional amine groups with carboxyl groups inherently tends toproceed at a greater rate at higher temperatures than those temperatureswhere phenolic thermosetting reactivity occurs. As those skilled in theart will appreciate, resole self-thermosetting capability can be made tovary over a very wide range of amine-substitution. Hence, during amolding operation, the phenolic portion of the resole resin tends tocure, while during subsequent post-curing operation at highertemperatures, the amine-carboxyl reaction tends to proceed.

In addition, and also unexpectedly, it has now been discovered thatcompositions of amine-modified resole resin and aromatic polycarboxyliccompound can be partially precured before use in a molding operation soas to produce thermosettable molding compositions which have controlledviscosity and flow characteristics, so that a product partially precuredresin system of this type can be fabricated so as to have an optimum setof viscosity and flow characteristics for a given molding operation orfor a given molding machine.

Also, and unexpectedly, it has now been discovered that compositions ofamine-modified resole resin and aromatic polycarboxylic compound, evenwhen molded at the lower temperatures above indicated, generally cure atsignificantly more rapid rates than compositions of aromaticaminemodified novolac resin and aromatic polycarboxylic compound. Thiscircumstance not only reduces the total quantity of thermal energyneeded to achieve substantially complete crosslinking (thermosetting)whereby maximum continuous service temperatures are achieved, but alsoimproves the initial strength characteristics of a molded body duringits initial molding to the point where volatiles evolution therefrom, asin a subsequent heat treating operation (where thermosetting iscompleted), is far less likely to damage such body, as throughblistering, swelling, distortion or the like.

Because amine-modified resole resins can be prepared in the form ofrelatively low molecular weight resins which polymerize (and thermoset)on heating, one can prepare compositions of aromatic amine modifiedresole resins and aromatic polycarboxylic compounds in the form ofsolutions, varnishes, dispersions, emulsifiable solutions andsuspensions, in a manner not unlike that now conventionally done withresole resins generally. The result is that such compositions can beused to impregnate and treat porous substrates, and thereby make suchindustrial products as high temperature fluid filters, high temperaturelaminates, etc., which is a result difficult to achieve with novolacsand amine-modified novolacs owing to the fact that the inherent highmolecular weight of such materials substantially prevents or makes verydifficult the preparation of liquid solutions or dispersions thereof onan industrial scale.

SUMMARY The present invention relates to new and useful thermosettablephenolic resin compositions of matter, to partially thermosetcompositions produced therefrom, the thermoset products made therefromand to methods for making the same. These compositions comprise at leastone amine modified resole resin and at least one aromatic polycarboxyliccompound. Such an amine-modified resole resin is generally characterizedby having:

1. a number average molecular weight of from about to 800,

2. a combined aldehyde to aniline plus phenol ratio of from about 0.9 to2.0, 3. a mol ratio of aromatic amine to phenol in the range of 75:25 to10:90.

Similarly, such an aromatic polycarboxylic compound is characterized asbeing within the class of compounds having the general formula: 0'

R; /O (COOH) (C0OR 0 ll 0 n in which R, is an aromatic radical of three,four, five, or six valences and containing from six to 24 carbon atoms,R, is a monovalent hydrocarbon radical containing less than 19 carbonatoms; n is an integer of from 0 through 3; m is an integer of from 0through 6; p is an integer of from 0 through 6; when n is 0, the sum ofm+p is an integer of from 3 through 6; when n is l, the sum of m+p is aninteger of from 1 through 4; when n is 2, the sum of m-l-p is an integerof from through 2; and the sum ofn and p is always at least 1.

Preferably, R contains a single six membered aromatic ring (i.e. phenyl)or a benzophenone nucleus, and R is a lower alkyl radical. The termlower as used herein refers to a radi- 5 cal containing less than sevencarbon atoms.

In general, the amine-modified resole resins as characterized abovethermoset by heat alone; for example, when exposed to a temperature ofabout 380 F. without pressure.

For each 100 parts by weight of that amine-modified resole 1o resin in acomposition of this invention, one usually employs from about 5 to 200parts by weight of aromatic polycarboxylic compound, though quantitiesof from about to 90 are preferred.

DETAILS For purposes of this invention, the term thermoset" orthermosettingd in reference to starting or product compositions of thisinvention indicates that a given thermosettable 2O composition, afterexposure to elevated temperatures for times sufficient to substantiallycompletely react together substantially all of one of the two components(depending upon which one is present in excess of stoichiometric amount)with the other component comprising a composition of this inven- (orextractability) in common organic solvents, such as methyl ethyl ketone,so that not more than about 10 weight per cent of a given so thermosetproduct dissolves in such a solvent. Similarly, the term substantiallyinfusible" has reference to the fact that a given or thermoset productdoes not appreciably melt before decomposing when heated to elevatedtemperatures.

Typical aromatic amine beginning materials suitable for use in makingthe aromatic amine-aldehyde resins used in this invention are aromaticamines which have at least one primary amine group, or at least onesecondary amine group substituted on an aromatic nucleus per molecule.

Typical beginning materials suitable for use in making amine-modifiedresole resins are:

A. a phenol which has at least one unsubstituted reactive position onthe aromatic nucleus,

B. an aromatic amine which has at least one primary amine group or atleast one secondary amine group substituted on an aromatic nucleus, and

C. an aldehyde containing at least one aldehyde group.

The phenols which can be employed in this invention are aromaticalcohols which have at least one hydroxyl group directly attached to thearomatic nucleus and which have at least one unsubstituted reactiveposition on the aromatic nucleus. It is normally the case that thereactive positions on Preferred phenols are phenol itself, alkylphenols,and aryl 0 phenols wherein substituents on this phenol benzene ring havea total of from one to 18 carbon atoms, and most preferably, from one tosix carbon atoms.

The aromatic starting amines which can be employed can be of manydifferent types. Thus, it can be a class represented by the formula:

ArNl-l wherein Ar is an aryl group which has at least one unsubstitutedreactive position on the aromatic nucleus. it can also be a classrepresented by the formula:

( ArlTl ll (3) wherein Ar is as just defined and R is an alkyl radical,an aryl radical, an aralkyl radical, an alkaryl radical, or the like.Preferably, in formulas (2) and (3), Ar is a phenyl radical and R,contains less than i 1 carbon atoms.

Ordinarily in both formula (2) and formula (3) amines, the reactivepositions are those which are ortho and para to the amino group.Accordingly, aromatic amines which have at least one unsubstitutedposition ortho or para to the amino group are preferred for use inpreparing the condensation products employed in the invention. Thepresently most preferred aromatic amines are aniline, thealkyl-substituted anilines wherein the alkyl groups thereof have fromone to four carbon atoms, and the alkyl-substituted diaminobenzeneswherein the alkyl groups thereof have from one to four carbon atoms.

The amines operative in the present invention can be aromatic diamines.Both aromatic primary and secondary diamines are operative in thepresent invention, but the aromatic primary diamines are preferred overthe secondary because the secondary diamines are less desirable as thethermal stability and hydrolytic stability are apparently less than theprimary diamines. The diamines are of the general formula:

2 e- 2 wherein R is a divalent aromatic radical. Also operative arearomatic diamines having the general formula:

H N--R -NHR, (5) wherein R is as above defined and R is an alkylradical, an aryl radical, an aralkyl radical, an alkaryl radical, or thelike. Preferably, R is a phenyl radical and R is a lower alkyl radical.

The aldehydes which can be employed are alkanals such as formaldehyde,acetaldehyde, propionaldehyde and the like, aromatic aldehyde such asbenzaldehyde, salicylaldehyde, and the like, haloalkanals, such aschloral, and the like. Formaldehyde is preferred. The formaldehyde canbe employed in water solution or dispersion, or in an organic solventsuch as methanol. It is preferred to employ the formaldehyde in aqueoussolution (such as the 37 weight per cent aqueous solution known asformalin). Paraform can also be used.

Sometimes, if desired, the phenol and the aromatic amine can be combinedinto a single starting compound wherein the same aromatic nucleus hassubstituted thereon at least one hydroxyl group and at least one primaryor secondary amine group. Similarly, if desired, the phenol and thealdehyde can be combined into a single starting compound wherein the 0same aromatic nucleus has substituted thereon at least one aldehydegroup and at least one hydroxyl group. Similarly, if desired, thearomatic amine and the aldehyde can be combined into a single startingcompound wherein the same aromatic nucleus has substituted thereon atleast one aldehyde group and at least one primary or secondary aminegroup.

When such a composite polyfunctional starting material is employed, itis preferred to use such in admixture with an aromatic amine, a phenol,and an aldehyde. For example, one could employ up to about 50 weight percent of such a polyfunctional starting material in making an aminemodified resole.

When one makes an amine-modified resole resin using, for example, aphenol, an aromatic amine and an aldehyde, it is convenient andpreferred to condense the starting materials under aqueous liquid phaseconditions using heat and a base catalyst. Conventional and preferredbase catalysts are organic and inorganic bases which are relativelystrong as respects their disassociation constants. Examples of suitablesuch base catalysts include: calcium and barium hydroxides, ammonia,tertiary and quarternary organic amines (triethyl amine, and the like).

The amount of base catalyst employed can vary but, in general, issufiicient to produce a pH in an aqueous liquid phase medium offromabout 7.0 to 9.5 (preferably from about 7.5 to 8.5) but this is notnecessarily a critical factor.

The proportion of reactants employed is likewise not necessarily acritical factor, and can be varied over a wide range. For example, themol ratio of aromatic amine groups to phenolic -Ol-l groups ranges fromabout 75/25 to /90 and the mol ratio of aldehyde to the sum of aromaticamine groups plus phenolic -Ol-l groups ranges from about 1.0 to [.5 Forinstance, in a preferred specific embodiment, the charged mol ratio ofaniline to phenol can range from about 50/50 to /80, though a morepreferred range is from about 40/60 to /70. Similarly, and for example,the charged mole ratio of formaldehyde to the sum total of aniline andphenol is less than about 2.5.

For such a preferred condensation, the base catalyst is preferablytriethylamine, ammonia or barium hydroxide in an amount of about 0.2 to3 parts per 100 parts phenol (by weight). The temperature of reactantsin such preferred embodiment can vary from about 60 to 100 C. Agitationof reactions during condensation is preferably continuous. The entireaddition and condensation reactions may be carried out at refluxtemperatures if desired. Since co-reactions are apparently involved, thereaction mechanism, it is theorized, may involve formation of lowmolecular weight intermediates which initially form, and then possiblyrearrange and combine with one another at a later stage. Typically,addition and condensation reaction conditions are maintained until allaldehyde is consumed.

ln general, conventional equipment can be employed for the reactions.For example, a reaction kettle equipped with agitator, means for refluxand distillation, nitrogen inlet means, and conventional heat transfermeans is suitable. The material of construction can be steel, stainlesssteel, glass, Monel, or the like.

In general, a preferred method for carrying out the reaction of thephenol, aldehyde, and amine starting materials is to charge the phenol,aldehyde, and base catalyst and then add the aromatic amine. Thismixture is brought to reflux at a temperature of from about 50 C. toabout 100 C., and preferably from about 60 C. to about 80 C. usingvacuum as required to control temperature. The reaction is continued forabout 30 minutes to about 4 hours or until essentially all of thealdehyde is reacted At the end of the reaction period, the product canthen be recovered by stripping off water and unreacted reagents underreduced pressure at temperatures from about C. to about 100 C., andpreferably, from about 60 to about 95 C.

Aniline phenol-formaldehyde resins prepared as just described generallyhave the above-described characteristics and constitute a preferredclass of amine-modified phenolic resins suitable for use in the presentinvention.

In general, for use in the present invention, amine-modified resoleresins are prepared in the form of substantially anhydrous startingmaterials, as explained above.

An advantage in dehydrating a starting amine-modified resole is that thedehydration procedure (using heat and reduced pressure as describedabove) typically also tends to remove impurities from a starting resin,such as unreacted starting materials, catalysts, etc.

Turning to the aromatic polycarboxylic compounds of formula (1), it willbe appreciated that R the monovalent hydrocarbon radical, is not acritical function in the present invention, and may be any monovalentalkyl, aryl, or even a cycloalkyl, halogenoalkyl, halogenoaryl or otherhalo-substituted radical (preferred chloro). The preferred monovalenthydrocarbon radicals are alkyl radicals, especially those containingfrom one through 10 carbon atoms. The aromatic carbonyl-containingcompound must contain at least two carbonyl-containing groups in theortho position. The anhydride groups, each with a valence of two, andeach containing two carbonyl-containing groups, are always attached toadjacent carbon atoms on an aromatic ring. The formula (1) compounds cancontain any combination of anhydride, acid, or ester groups, as definedin formula l A preferred number of carbonyl-containing groups permolecule is four, such as two anhydride groups, four acid groups, fourester groups or a combination of any four of these carbonyl-containinggroups. A particularly preferred aromatic carbonyl containing compoundis benzophenone tetracarboxylic acid dianhydride. The aromatic radicalsmust each contain at least two carbonylcontaining groups attached toadjacent carbon atoms whereas the other carbonyl-containing groups canbe on any other ring position.

As a class, the compounds of formula l) are known, as are methods fortheir preparation (so details concerning the latter are not givenherein).

Preferably, for use in the present invention, aromatic polycarboxyliccompounds are prepared in the form of substantially anhydrous startingmaterials, as explained above.

To make a thermosettable resinous composition of this invention, onetakes an amine-modified resole resin as described above and an aromaticpolycarboxylic compound as described above and simply mixes the twocomponents together until a substantially uniform product mixture isobtained. The relative proportions of each are as broadly describedabove. The optimum proportions of amine-resole resin to aromaticpolycarboxylic compound are determined in an individual situation by anumber of variables such as the aminecontent of the resole resin, themolecular weight and reactivity of the aromatic polycarboxylic compound,degree of thermal stability desired in a given thermoset product,processability parameters, molding equipment limitations, and the like.Hence, it is not possible to express precisely an optimum ratio ofaminemodified resole resin.

In general, the proportion of aromatic polycarboxylic compound toamine-modified resole resin in any given thermosettable composition isbased on the amount of aromatic amine in the resin used. Preferably theproportion of aromatic polycarboxylic compound to amine-modified resoleresin is such that amide, imide, and/or ester linkages can be formed ateach amine hydrogen and each phenolic hydroxyl site within each aminemodified resole resin molecule. However, useful compositions arefrequently achievable by using less than all such amine hydrogen andphenolic hydroxyl sites when crosslinking with an aromaticpolycarboxylic compound such as taught in this invention. Also, utilityis not appreciably affected, within wide limits, by using excesses ofstoichiometric amounts of aromatic polycarboxylic compounds in relationto a given quantity of aniline-modified resole resin. Duringthermosetting, it should be noted that at higher temperatures, e. g.temperatures say above 200 C or more, typically, though not necessarily,rearrangements can occur in the thermoset material which result in ahigher concentration of one form of linkage as opposed to another. Forexample, it is tentatively theorized (and there is no intent to be boundby theory herein) that at higher temperatures, rearrangement to formimide linkages is common in a given thermoset product of this invention.

In general, the thermosettable resinous compositions of this invention,owing to the initial substantially dehydrated character of each of theamine-modified resole resin and of the aromatic polycarboxyliccompounds, respectively, employed in these compositions, are in the formof either powders which are characteristically free flowing, or liquidswhich are in the form of solutions or dispersions with the liquid mediumthereof being organic and substantially anhydrous in character.

When making a solid, thermosettable composition of this invention, it ispreferred to use an amine-modified resole resin and an aromaticpolycarboxylic compound(as described above, respectively) in the form ofsolids which have particle sizes generally under about 50 mesh (U.S.Standard sieves). Preferably, particle sizes under about mesh are used.The admixing of one component with the other can be made in a blender,such as a so-called Waring blender, a ball mill, or the like, althoughany convenient mechanical mixing means may be employed.

On the other hand, when preparing a liquid thermosettable composition ofthis invention, either or both the aminemodified resole or the aromaticpolycarboxylic compound may initially be in a solid or liquid form.Thus, the aminemodified resole resin even in its substantially anhydrousform may be in a liquid condition. Although the aromatic polycarboxyliccompound even in its dehydrated form may also be in a liquid condition,typically such aromatic polycarboxylic compound is in the form of a highmelting solid.

As indicated, an organic liquid is used to dissolve or disperse eitheror both the amine-modified resole resin and the aromatic polycarboxyliccompound. in general, the organic liquid used is one which is:

l. substantially inert (as respects each of the amine modified novolacresin and the aromatic polycarboxylic compound).

2. boils below about 250 C. (preferably 150 C.) at atrnospheric,

3. is a mutual dispersant for both the amine modified novolac resin andthe aromatic polycarboxylic compound, and

4. is substantially single phased.

By the term mutual dispersant" as used herein reference is had to thefact that a given organic liquid is capable of acting either as asolvent and/or as a colloidal suspending medium for the amine modifiedresole resin and for the aromatic polycarboxylic compound in a productthermosettable composition of this invention. As used herein, the termcolloidal" is reference to a suspension or dispersion has reference tosuspended or dispersed solid particles which are under about 200millimicrons in average maximum individual particle size dimension.

By the term substantially single phased" reference is had to the factthat a given organic liquid exists in a liquid composition of thisinvention as one phase.

While the organic liquid used has properties as indicated above. it willbe appreciated that such a liquid in a particular composition of theinvention can comprise mixtures of two or more chemically differentorganic liquids. For example, one can preliminarily dissolve or dispersethe amine modified resole resin in one particular liquid, and thearomatic polycarboxylic compound in another particular organic liquid,and then thereafter mix the two resulting such organic liquids together.Obviously, when one uses such a mixture of different organic liquids,the liquids are so chosen as to be mutually intermiscible with oneanother at least in the respective amounts of the individual organicliquids employed in a given product mixture in order to obtain acompatible one phase liquid medi- It is desirable and preferred to havea single phase organic liquid in liquid thermosettable compositions ofthis invention because of the possibility of having a concentrationeither of aromatic polycarboxylic compound or of amine modified resoleresin which is greater in one liquid phase than in the other. Such aconcentration differential could possibly lead to irregularities andnon-uniformities in a thermoset composition derived therefrom, as thoseskilled in the art will appreciate.

Preferred organic liquids (especially when one is using) as the organicliquid a single chemical entity, are lower alkanones, such as acetone,methyl ethyl ketone or higher ketone. On the other hand, when one usesas the organic liquid a mixture of difierent organic entities, one canemploy as preferred liquids lower alkanols (such as methanol or ethanol)or aliphatic, cycloaliphatic or aromatic hydrocarbons, includingbenzene, toluene, xylene, naphthalene, nonane, octane, petroleumfractions, etc. Conveniently, some of the organic liquid present can beexcess alcohol left over from an esterification reaction involving anaromatic polycarboxylic compound. Any given organic liquid used in acomposition of this invention is substantially anhydrous, as indictedabove.

Preferably, the amine modified resole resin starting materials aresubstantially completely dissolved in the organic liquid phase of aliquid composition of this invention. If not so dissolved, thenon-dissolved portion thereof is in the form of a colloidal dispersionor suspension of particles. Preferably, at least percent of the aminemodified resole resin is completely dissolved in the organic liquid andmore preferably such resin is substantially completely dissolved in theorganic liquid.

Similarly, the aromatic polycarboxylic compound starting materials aresubstantially completely dissolved in the organic liquid phase of aliquid composition of this invention. If not so dissolved, thenon-dissolved portion thereof is in the form of a colloidal dispersionor suspension of particles. Preferably, at least 80 percent of thearomatic polycarboxylic compound is completely dissolved in the organicliquid and more preferably such resin is substantially completelydissolved in the organic liquid.

Those skilled in the art will appreciate that organic solvents can beadded to a given liquid composition of this invention to improve thequantity of respective starting materials in true solution. For example,adding a ketone or an ester ether solvent, or even a so-called super"solvent, such as dimethyl formamide, will generally improve the abilityof a given composition to dissolve both classes of component startingmaterials. If dimethyl forrnamide is employed, it is preferred to usenot more than about 20 weight percent of this material based on totalorganic liquid weight in a given liquid composition.

The respective concentrations of the amine modified resole resin and ofthe aromatic polycarboxylic compound in a given liquid composition ofthis invention relative to the total amount of organic liquid presentcan vary over extremely wide ranges. A rough but practical indication ofthe concentration of the respective starting materials in a given liquidcomposition is given by the viscosity of such a composition. Acorrelation between viscosity and particular contemplated end use camsometimes be made, as those skilled in the art will readily appreciate.characteristically, though not limitatively, a liquid composition ofthis invention can have viscosities ranging from about 10 to 5,000centipoises. For impregnating applications, viscosities of from about50-500 centipoises are usually preferred. The total solids content of agiven liquid composition can be as high as about 75 weight percent oreven higher, and as low as about 20 weight percent or even lower.Preferred solids contents usually fall in in the range of from about 50to 70 weight percent as those skilled in the art will readilyappreciate.

Liquid compositions of this invention can be advanced (e.g. crosslinkedas by heating) to some extent without forming precipitates from theorganic liquid. Advancing can be accomplished if desired by heating attemperatures generally in the range of from about 70 to l00 atatmospheric pressures for times typically in the range of from about 20to 30 minutes or even longer, care being taken not to cause solidmaterial to precipitate.

in both the solid and the liquid compositions of this invention, it willbe appreciated that the ratio of amine modified resole resin to aromaticpolycarboxylic compounds is as indicated above. However, mixtures ofdifferent amine modified resole resins and of different aromaticpolycarboxylic compounds can be employed in any given composition toenhance characteristics desired for a particular end use application asthose skilled in the art will readily appreciate.

Those skilled in the art will readily appreciate that variousconventional additives can be composited with the solid or liquidcompositions of this invention to promote effectiveness for particularend uses. For example, one can add dyes, colorants, release agents,fungicides, coupling agents, and the like.

In the case of the powdered products of this invention, one can addparticular solid diluent materials to produce molding compositions. Forexample, a typical molding composition using a composition of thisinvention contains from about 25 to 40 weight percent of a compositionof this invention, and, correspondingly, from about 60 to 75 weightpercent of particulate inert diluent. A molding composition typicallycontains in addition from about 1 to 2 weight percent of a lubricant andfrom about 1 to 2 weight percent of a colorant,

though relatively higher percentages of these last indicated componentscan be present herein.

USES

As indicated above, the solid compositions of this invention can be usedas molding powders. In general, conventional molding powder technologycan be employed in the utilization of such solid compositions. Sometimesit is desirable in order to avoid blistering to cool a given mold asthose skilled in the art will appreciate. The solid resins can also beused to bond aluminum oxide grits commercially utilized in abrasives.

The liquid compositions of this invention find use for-impregnation andreinforcing purposes. Thus, the liquid compositions can be used toimpregnate cellulosic paper, asbestos paper and other known woven sheetstructures as well as woven fabrics (such as glass fibers, cottonfibers, nylon fibers, etc.) and the like. Impregnation can beaccomplished by any conventional or convenient means including dipping,coating, spraying, or the like. The so-impregnated material isconventionally air-dried to lower the volatiles content and then isheated to advance the composition of this invention to a particulardesired degree for the ultimate intended use. The soimpregnated sheetmaterials are themselves particularly useful in the manufacture oflaminates. Such laminates, such as those made from impregnated sheetmaterials as indicated above are useful in electrical applications assupports or as insulation for conductive elements. The laminates so madeare particularly characterized by superior heat resistance and thermalstability characteristics. The laminates are generally manufactured in asheet or block form which is then machined to provide desiredconfiguration for a particular end use.

Oil filters, such as for use in automobiles, can be prepared from theimpregnated sheet members produced as generally described above. Forexample, one can impregnate with a liquid composition of this inventioncellulosic papers modified with a synthetic fiber such as a polyester orthe like and having a thickness of from about to 20 mils. Sufficientliquid composition is used to impregnate such a sheet member so that theproduct sheet member when cured has a resin content of from about 15 to25 weight per cent based on the total product weight. After such a paperis impregnated, it is typically heated to partially advance the resincomposition, and hen is corrugated or pleated to form a filter element.The filter element is then assembled with an end use filter condenserand the whole assembly is heated to say from about 250 to 350 F. forfrom about 5 to 20 minutes to cure the resin. When cured, the producthas excellent high temperature characteristics.

In addition, a liquid composition of the present invention can be usedto make reinforced plastics.

In this invention, all solids in liquids are conveniently measured usingASTM Test Procedure D-l 15-55.

EMBODIMENTS The following examples are set forth to illustrate moreclearly the principles and practices of this invention to one skilled inthe art and they are not intended to be restrictive but merely to beillustrative of the invention herein contained. Unless otherwise statedtherein, all parts and percentages are on a weigh basis.

The following examples illustrate preparation of aminemodified phenolicresole resins:

EXAMPLE A Preparation of Aromatic Amine-Modified Phenolic Resole Resin1800 Grams (19.2 moles) of phenol and 2400 grams (29.6 moles) of 37 percent formalin are charged to a 3 gallon stainless steel reaction kettleequipped with a horseshoe agitator, thermometer, condenser andnecessary. piping. The temperature is adjusted to about 35 C. 36 Gramsof triethyl amine (0.36 moles) are added. Next, over about a 5 minuteperiod,

600 grams (6.45 moles) of aniline are added to the reaction mixture. Thetemperature rises rapidly to about 50 C. but then levels ofi". Thereaction mixture is brought to a 75 C. reflux under vacuum (about 6psia) and maintained at this temperature for 45 minutes. At the end ofthe reflux time, the kettle is changed over to dehydration with thevacuum being increased slowly to about 1.0 psia. Distillation iscontinued until the resin is grindable by test (usually at about 85-90C. with 1.0 psia vacuum). When a sample of the resin is grindable(completely brittle at room temperature), the batch is poured into a panto cool. A fan is used to cool the resin rapidly to room temperature.The resulting aromatic amine-modified phenolic resole lump resin is anessentially clear, ambercolored, low melting solid at room temperature.The yield of solid resin is about 155 per cent on the phenol charge.

1600 Grams (17.0 moles) of phenol and 2560 grams (31.6 1

moles) of 37 per cent formalin are charged to a 3 gallon stainless steelreaction kettle equipped with a horseshoe agitator, thermometer,condenser and necessary piping. The temperature is adjusted to about 35C. 16 Grams (0.1 1 moles) of hexamethylene tetramine are added. Next,over about a 5 minute period, 960 grams (10.3 moles) of aniline areadded to the reaction mixture. The temperature rises rapidly to about 60C., but then levels off. The reaction mixture is brought to anatmospheric reflux (about 100 C.) and maintained at this temperature forabout 4 hours. At the end of the reflux time, the kettle is changed overto vacuum dehydration and vacuum slowly applied up to 10 psia (about 90C.). After about 1 /2 hours, the vacuum is increased so as to lower thetemperature to about C. (about 7 psia). As the temperature rises, vacuumis increased step-wise until 1.0 psia is obtained at about C.Distillation is continued until the resin is grindable by test (usuallyat about 95 C. with 1.0 psia vacuum). When a sample of the resin isgrindable (completely brittle at room temperature), the batch is pouredinto a pan to cool. A fan is used to cool the resin rapidly to roomtemperature. The resulting aromatic amine-modified phenolic resole lumpresin is an essentially clear, amber-colored, low melting solid at roomtemperature. The yield of solid resin is about per cent on the phenolcharge.

EXAMPLES C-H Following the same general procedures described in ExamplesA and B, a series of amine-modified phenolic resins are EXAMPLES J-SFollowing the same general procedure describes in Examples A and B, aseries of amine-modified phenolic resins are prepared using varioussubstituted phenols and aromatic amines. Table 11 below describes eachresin:

tion cycle. The resulting solution is a clear, amber-colored liquid ofmedium viscosity. To this solution is added'860 grams of k dibutyl esterof benzophenone tetracarboxylic acid dianhydride solution from ExampleT. With sufficient mechanical blending, the mixture gives aclear,amber-color varnish. When a small amount (1-2 grams) is placed on a hotplate at about 180 C., this varnish cures to ahard thermoset resinfollowing evaporation of the solvent. Cellosolve is ethylene glycolmonoethyl ether.

EXAMPLES 2-7 Preparation of Varnish Following the same proceduredescribed in Example 1, a series of varnishes are preparedfrom'aminemodified phenolic resins and aromatic polycarboxyliccompounds. Table III below describes each resin:

TABLE Ill Resin ldenti- B fication (Ex. No.) Part A Solvent ResinConcentration Part B Aromatic Polycarboxylic Compound Ratio by wt. of Ato B in final varnish Methyl mar ethyl ketone Ethyl Methyl butyl ethylketone ketone Methyl ethyl ketone Cellosolve T BTDA" V X T l/l.3 l/0.41/0.2 1/2.4 1/2.3 lll.5

'Benzophenone Tetracarboxylic Acid Dianhydride EXAMPLE 8 Preparation ofThermosetting Resin Powder from Aromatic Amine-Modified Phenolic ResoleResin and an Aromatic Polycarboxylic Compound 500 Grams of resin fromExample A, 260 grams of aromatic polycarboxylic compound from Example Jand 10 gram of calcium stearate are ground together in a laboratory ballmill 7 until essentially all of the material passed U.S. sieve no. 140.

The product is a tan colored resin powder. When a small amount (1 -2grams) is placed on a hot plate at about 180 C. this resin melts andthen cures to a hard thermoset resin.

EXAMPLES 9-10 Following the same general procedure described in Example7, a series of resin powders are prepared from aminemodified phenolicresins and aromatic polycarboxylic com- PART A Sheets of glass clothE.C.D. 225-181 finished with gammaaminopropyltriethoxysilane areimpregnated by dipping the cloth in the resin solution prepared inExample 1, and removing the excess resin solution by drawing the clothover a scraper bar. The impregnated cloth is heated in an oven for aboutone-quarter hour at about 135 C. to remove the solvent from theimpregnated cloth and to partially advance the resin. The resultingcloth contains about 40 per cent resin solids and about 6 per cent ofvolatiles.

PART B A series of laminates one-eight inch thick are prepared from 12sheets of resin impregnated cloth prepared as described in Part A. The12 plies of cloth are laid up with the warp running in the samedirection in all plies and the assembly is pressed under a pressure ofapproximately 300 p.s.i. at a temperature of 350 F. for minutes. Afterbeing removed from the mold, the laminate is post-cured by being heatedin an air-circulating oven in accordance with the following schedule:

24 hours at 310 F.

24 hours at 350 F.

24 hours at 400 F. pl 4 hours at 450 F.

48 hours at 500 F.

These laminates have ilexural strengths in the range of from about70,000 to 90,000 p.s.i. at 75 F. The above and all subsequently reportedflexural strength values are measured by Federal Specification LP406Test Method No. 103 1.

PART C The laminates prepared in Part B above are maintained in anair-circulating oven for hours at 600 F. The flexural strengths of thelaminates are then determined at 600 F. with values of from about 30,000to 50,000 p.s.i. being obtained.

What is claimed is:

l. A thermosettable resin composition comprising in combination on a 100weight per cent total basis:

A an aromatic polycarboxylic compound of the formula:

II a 0 n in which R is an aromatic radical of three, four, five, or sixvalences and containing from six to 24 carbon atoms, R, is a monovalenthydrocarbon radical containing less than 19 carbon atoms; n is aninteger of from 0 through 3; m is an integer of from 0 through 6; p isan integer of from 0 through 6; when n is 0, the sum of m+p is aninteger of from 3 through 6; when n is l, the sum of m+p is an integerof from 1 through 4; when n is 2, the sum of m+p is an integer of from 0through 2; and the sum of n and p is always at least 1,

B. an aromatic amine-modified resole resin condensate of an aldehyde, anaromatic amine and a phenol havinG at least one reactive unsubstitutedposition on the aromatic nucleus, the resin being characterized byhaving:

1. a combined aldehyde to aromatic amine plus phenol ratio of from about1.0 to 2.5; 2. a mol ratio of aromatic amine to phenol in the range of75:25 to 10:90; wherein the amounts of reactants are such that for each100 parts by weight of said aromatic amine-modified resole resincondensate there are from 5 to 200 parts by weight of said aromaticpolycarboxylic compound.

2. A composition of claim 1 wherein the phenol is selected from thegroup consisting of phenol, t-butylphenol, p-phenylphenol,p-nonylphenol, p-chlorophenol, alpha-naphthol, 3,5-xylenol andbis-phenol A.

3. A composition of claim 1 wherein the aromatic amine is selected fromthe group consisting of aniline, o-toluidine and o-chloroaniline.

4. A composition of claim 1, wherein the aldehyde is formaldehyde.

5. A thermoset composition of claim 1.

6. A composition of claim 1 wherein said compounds are suspended in anorganic solvent medium.

7. A composition of claim 1 wherein said aromatic polycarboxyliccompound is an ester of trimellitic anhydride.

8. A composition of claim 1 wherein said aromatic polycarboxyliccompound is an ester of benzophenone tetracarboxylic anhydride.

9. A composition of claim 1 wherein said aromatic polycarboxyliccompound is an ester of pyromellitic anhydride.

10. A thermosettable resin composition comprising:

A. an aromatic polycarboxylic compound selected from the groupconsisting of mellitic anhydride, pyromellitic dianhydride, andbenzophenone tetracarboxylic acid dianhydride, mellitic acid dialkylester, pyromellitic acid dialkyl ester, pyromellitic acid tetraalkylester,

benzophenone tetracarboxylic acid dialkyl ester and benzophenonetetracarboxylic acid tetraalkyl ester, wherein the alkyl groups containone to six carbon atoms;

B. an aniline-modified phenol formaldehyde condensate prepared underbasic conditions, characterized by havmg: l. a number average molecularweight of from about 150 to 800; 2. a combined formaldehyde to anilineplus phenol mol ratio offrom 1.0 to 2.0; 3 a mo] ratio of aniline tophenol in the range of 50:50 to 20:80; there being for each 100 parts byweight of said anilinemodified resole from 5 to 200 parts by weight ofsaid aromatic polycarboxylic compound.

11. A thermosettable resin composition of claim 10, wherein there arebetween 15 and parts by weight of aromatic polycarboxylic compound foreach I00 parts by weight of aniline-modified resole.

2. a mol ratio of aromatic amine to phenol in the range of 75: 25 to10:90; wherein the amounts of reactants are such that for each 100 partsby weight of said aromatic amine-modified resole resin condensate thereare from 5 to 200 parts by weight of said aromatic polycarboxyliccompound.
 2. A composition of claim 1 wherein the phenol is selectedfrom the group consisting of phenol, t-butylphenol, p-phenylphenol,p-nonylphenol, p-chlorophenol, alpha-naphthol, 3,5-xylenol andbis-phenol A.
 2. a combined formaldehyde to aniline plus phenol molratio of from 1.0 to 2.0; 3 a mol ratio of aniline to phenol in therange of 50:50 to 20: 80; there being for each 100 parts by weight ofsaid aniline-modified resole from 5 to 200 parts by weight of saidaromatic polycarboxylic compound.
 3. A composition of claim 1 whereinthe aromatic amine is selected from the group consisting of aniline,o-toluidine and o-chloroaniline.
 4. A composition of claim 1, whereinthe aldehyde is formaldehyde.
 5. A thermoset composition of claim
 1. 6.A composition of claim 1 wherein said compounds are suspended in anorganic solvent medium.
 7. A composition of claim 1 wherein saidaromatic polycarboxylic compound is an ester of trimellitic anhydride.8. A composition of claim 1 wherein said aromatic polycarboxyliccompound is an ester of benzophenone tetracarboxylic anhydride.
 9. Acomposition of claim 1 wherein said aromatic polycarboxylic compound isan ester of pyromellitic anhydride.
 10. A thermosettable resincomposition comprising: A. an aromatic polycarboxylic compound selectedfrom the group consisting of mellitic anhydride, pyromelliticdianhydride, and benzophenone tetracarboxylic acid dianhydride, melliticacid dialkyl ester, pyromellitic acid dialkyl ester, pyromellitic acidtetraalkyl ester, benzophenone tetracarboxylic acid dialkyl ester andbenzophenone tetracarboxylic acid tetraalkyl ester, wherein the alkylgroups contain one to six carbon atoms; B. an aniline-modified phenolformaldehyde condensate prepared under basic conditions, characterizedby having:
 11. A thermosettable resin composition of claim 10, whereinthere are between 15 and 90 parts by weight of aromatic polycarboxyliccompound for each 100 parts by weight of aniline-modified resole.